Pulpitis and periapical periodontitis is a type of bacterial infectious disease, and bacteria frequently plant in the entire root canal system during the terminal stage. Main clinical treatment strategy of the disease requires root canal therapy, a key and core procedure for the successful treatment by thoroughly removing the root canal infection. The premise and guarantee of thoroughly removing root canal infection is by determining the accurate root canal working length. However, methods of accurately determining root canal working length, especially determining the position of apical stop, has been a hot topic among endodontic specialists, frequently causing confusion among many clinicians. This review provides a brief introduction of the complexity of the apical root anatomical structure, the confusion in determining the position of apical stop, and the method to determine the root canal working length.

Objective  To investigate the mechanism of retinoic acid (RA) signal in dental evolution, RA is used to explore the influence of the mechanism on neural crest’s migration during the early stage of zebra fish embryos. Methods We divided embryos of wild type and transgenic line zebra fish into three groups. 1×10^-7 to 6×10^-7 mol·L^-1 RA and 1×10^-7 mol·L^-1 4-diethylaminobenzaldehyde (DEAB) were added into egg water at 24 hpf for 9 h. Dimethyl sulfoxid (DMSO) with the concentration was used as control group. Then, antisense probes of dlx2a, dlx2b, and barx1 were formulated to perform whole-mount in situ hybridization to check the expressions of the genes in 48 hpf to 72 hpf embryos. We observed fluorescence of transgenic line in 4 dpf embryos. Results We obtained three mRNA probes successfully. Compared with DMSO control group, a low concentration (1×10^-7 mol·L^-1) of RA could up-regulate the expression of mRNA (barx1, dlx2a) in neural crest. Obvious migration trend was observed toward the pharyngeal arch in which teeth adhered. Transgenic fish had spreading fluorescence tendency in pharyngeal arch. However, a high concentration (4×10^-7 mol·L^-1) of RA malformed the embryos and killed them after treatment. One third of the embryos of middle concentration (3×10^-7 mol·L^-1) exhibited delayed development. DEAB resulted in neural crest dysplasia. The expression of barx1 and dlx2a were suppressed, and the appearance of dlx2b in tooth was delayed. Conclusion RA signal pathway can regulate the progenitors of tooth by controlling the growth of the neural crest and manipulating tooth development.

Objective This study aimed to explore the effect of the up-regulation of Notch1 on osteoclastogenesis induced to osteoclasts by receptor activator for nuclear factor-κB ligand (RANKL) and macrophage colony-stimulating factors (MCSF) in vitro. Methods The bone marrow stem cells (BMSCs) of Rosa-notch1 mice were cultured and induced to osteoclasts by RANKL and MCSF. The BMSCs were transfected with the Ad-Cre-green fluorescent protein (GFP) virus or Ad-GFP virus. Total RNA from cells was extracted, and the gene expression levels of Notch1, Notch2, Notch3, Notch4, Delta1, Delta3, Delta4, Jagged1, Hes1, and tartrate resistant acid phosphatase (TRAP) were detected at the defined stage by reverse transcription-polymerase chain reaction (RT-PCR). Osteoclast formation was analyzed by TRAP assay. Results The number of TRAP-positive multinuclear cells of the experimental group significantly decreased compared with that of the control group. The mRNA expression levels of Notch1, Notch3, Jagged1, Delta3, and Hes1 of the experimental group were significantly higher than those of the control group, whereas the TRAP mRNA expression of the experimental group was significantly lower than that of the control group (P<0.05). Conclusion Up-regulation of Notch1 inhibit osteoclastogenesis of BMSCs induced by RANKL and MCSF in vitro.

Objective This work investigated mesenchymal stem cells (MSCs) modified with Runt-related transcription factor 2 (Runx2) therapy for bone regeneration in rabbit mandibular distraction osteogenesis. Methods Forty-eight New Zealand mature white rabbits were randomly divided into three groups after the rabbit model of mandibular distraction osteogenesis was established: reconstruction plasmid modified with Runx2 (group A), plasmid without Runx2 (group B), and the same dose of saline as control (group C). At the fifth day of distraction phase, MSCs with reconstruction plasmid modified with adv-hRunx2-gfp were injected into the distraction gap of group A. MSCs with reconstruction plasmid modified with adv-gfp was injected into the distraction gap of group B, whereas group C was injected with the same dose of saline. At 8 weeks after injection, all animals were sacrificed, and the distracted mandibles were harvested. The general imaging histological observation and three-point bending test were used for evaluation. Results CT plain scan and histological analysis confirmed that the amount of new bone forming in the distraction gap of group A was significantly higher than those in groups B and C. Dual-energy X ray and three-point bending test results also showed that the bone mineral density, bone mineral content, and maximum load of the distraction gap of group A were significantly higher than those of groups B and C (P<0.01). Conclusion Runx2-ex vivo gene therapy based on MSCs can effectively promote the bone regeneration in rabbit mandibular distraction osteogenesis and shorten the stationary phase. Therefore, reconstruction of craniofacial fracture would be a valuable strategy.

Objective We explored the expressions of the Notch and Wnt signaling pathways and their significance in the repair process of alveolar bone defects by establishing animal models with a composite of autologous bone marrow mesenchymal stem cells (BMSCs) and platelet-rich fibrin (PRF) to repair bone defects in the extraction sockets of rabbits. Methods A total of 36 two-month-old male New Zealand white rabbits were randomly divided into four groups, and the left mandibular incisors of all the rabbits were subjected to minimally invasive removalunder general anesthesia. BMSC-PRF compounds, single PRF, and single BMSC were implanted in Groups A, B, and C. No material was implanted in Group D (blank control). The animals were sacrificed at 4, 8 and 12 weeks after surgery, the bone defect was immediately drawn, and the bone specimens underwent surgery after four, eight, and twelve weeks, with three rabbits per time point. The expressions of Notch1 and Wnt3a in the repair process of the bone defect were measured via immunohistochemical and immunofluorescence detection. Results  Immunohistochemistry showed that the expressions of Notch1 and Wnt3a in Groups A, B, and C were higher than that in Group D at the fourth and eighth week after operation (P<0.05). By contrast, the expressions of Notch1 and Wnt3a in Group D were higher than those in Groups A, B, and C at the twelfth week (P<0.05). Immunofluorescence showed that the expressions of both Notch1 and Wnt3a reached their peaks in the new bone cells of the bone defect after four weeks following surgery and gradually disappeared when the bone was repaired completely. Conclusion Notch1 and Wnt3a signaling molecules are expressed in the process of repairing bone defects using BMSC-PRF composites and can accelerate the healing by regulating the proliferation and differentiation of BMSCs. Moreover, the expressions of Notch and Wnt are similar, and a crosstalk between them may exist.

Objective This study aimed to evaluate the vascular endothelial growth factor (VEGF) expression and permeability of vascular endothelial cell under microvibration. Methods Human umbilical vein endothelial cell (HUVEC) were cultured, randomly vibrated under low frequency of 0.2, 0.5, 2, 5 Hz, 30 min per day. The VEGF mRNA level was detected by Tagman probe real-time fluorescence quantitative polymerase chain reaction (PCR), and the VEGF protein expression level was detected by Western blot. The permeability of vascular endothelial cell was evaluated. Results  Compared with the blank control group, the mRNA and protein expression level of VEGF were significantly increased under 0.2, 0.5 Hz microvibration (P<0.05), and decreased under 2, 5 Hz microvibration (P<0.01). The vascular endothelial permeability increased under 0.2, 0.5 Hz microvibration (P<0.01), whereas the permeability decreased under 2, 5 Hz microvibration (P<0.01). Conclusion 0.2-0.5 Hz microvibration can up-regulate the expression of VEGF mRNA and protein in vascular endo- thelial, and increase the permeability.

Objective This study aimed to conduct a preliminary study on the possible role and significance of interleukin (IL)-12 and IL-27 in the pathogeneses of oral lichen planus (OLP). Methods Thirty cases of patients with OLP (fifteen cases of reticular OLP and fifteen cases of erosive OLP) were enrolled in this study, and twenty cases of healthy people served as controls. Lymphocyte subsets CD3+, CD4+, CD8+, CD19+, and CD16+56 [natural killer cell (NK)] were tested using flow cytometry, and humoral immunity [immunoglobulin (Ig)G, IgA, IgM, C3, C4] were examined using nephelometry assays. IL-12 and IL-27 contents in serum of patients with OLP and normal controls were detected through enzyme linked immunosorbent assay. The correlations between the levels of IL-12, IL-27, immune status, and clinical characteristics of patients with OLP were analyzed, respectively. Results CD3+, CD4+, and CD8+ in patients with OLP were markedly lower than the normal value, whereas CD19+ of OLP in patients was significantly higher than the normal value (P<0.05). IgM in patients with OLP was increased, whereas C4 was declined (P<0.05). IL-12 and IL-27 levels showed significant upregulation of OLP patients compared with control groups (P<0.05). Meanwhile, positive correlations existed between IL-12 and IL-27 levels in the serum of patients with OLP (r=0.912, P<0.01). No significant correlations of IL-12 and IL-27 expressions with clinical characteristics of OLP were found (P>0.05). Negative correlations of IL-12 and IL-27 levels with CD16+56(NK) cells were observed (r₁=-0.416, P₁=0.022; r₂=-0.392, P₂=0.032, respectively), whereas a positive correlation existed for IgG (r₁=0.445, P₁=0.014; r2=0.549, P2=0.002, respectively). Conclusion  A cellular immune dysfunction mainly dominate in patients with OLP, accompanied by some degree of humoral-immunity-function disorder. The abnormally high expressions of IL-12 and IL-27 are possibly synergized and promoted inflammation development in OLP. Its promotion takes place through the negative feedback regulation of humoral immune responses, which are involved in the regulation of immune mechanisms of OLP.

Objective  To clarify the related factors of marginal bone loss (MBL) around tissue level implants in the posterior part of the mandible. Methods A total of 116 tissue level implants were implanted in the mandibular posterior region of  76  patients. Patients’ information, including general characteristics, implant characteristics, implant site characteristics, and prosthesis characteristics, was recorded. Their cone beam computed tomography data were measured immediately after implant placement, 3 months later, and 3 and 12 months after prosthesis loading. The measurement of MBL was conducted by One Volume Viewer software. SPSS 20.0 was used for statistic analysis. Results Smoking, cortical bone thickness (CBT), collum angle (CA), and implant local sanitation showed significant differences with body mass loss (P<0.05). No significant differences were found among sex, age, length of implant, diameter of implants, implant systems, bone height, prosthesis type, and MBL (P>0.05). Conclusion The risk factors that caused MBL were smoking, thicker CBT, larger CA, and poor implant local sanitation. Among them, poor implant local sanitation had the highest correlation with MBL.

Objective  This study aims to assess the effects of desensitizing toothpaste containing stannous fluoride on dentine hypersensitivity by performing Meta-analysis of randomized controlled trials (RCT) involving the treatment of dentine hypersensitivity with stannous fluoride-containing toothpaste. Methods  The study was developed based on the Cochrane handbook for systematic reviews of interventions (Version 5.1.0) and included the following: search strategy, selection criteria, data extraction, and risk of bias assessment. We searched electronic databases such as CNKI, CBM, PubMed, Embase, and Cochrane Library up to January 2015. RCT of treating dentine hypersensitivity with stannous fluoride-containing toothpaste were included. Data extraction and domain-based risk of bias assessment were independently performed by two reviewers. Meta-analysis was performed with RevMan 5.3 software. Results  Six RCT with 494 patients (247 in the experimental group and 247 in the control group) were included. The results of Meta-analysis showed that the desensitizing effect of stannous fluoride-containing toothpaste was significantly better than that of control in tactile sensitivity test (SMD=1.41, 95% confidence interval 0.74–2.09, P<0.000 01) and air blast test (SMD=-1.16, 95% confidence interval -1.84–-0.48, P<0.000 01). Conclusion  Current evidence shows that stannous fluoride-containing toothpaste is effective in treating dentine hypersensitivity in clinic. However, due to limited sample size and lower quality of the included studies, more high quality and large-sample RCT are needed to further verify the evidence.

Objective  This research aimed to analyze the three-dimensional position of mandibular canal (MC) and mandibular morphology of normal young males and females by using data from cone beam computed tomography (CBCT), as well as to provide an anatomical basis for clinical surgery of the mandible. Methods Normal occlusion and CBCT scans of 29 normal young people were conducted. InVivo 5 software was used to reconstruct the mandible, anchor the points, and measure the jaw shape and three-dimensional course of MC. All measurements were analyzed with SSPS 17.0 software. Results  The MC lingual bone cortex was thinner than the MC buccal bone cortex, and the distance of the MC to the buccal bone cortex gradually increased. However, the distance of the MC to the tongue bone cortex and alveolar crest gradually decreased from proximal to distal. In addition, the distance of the MC to the mandibular lower margin was minimal at the first molar and reached the maximum at the second premolar. No significant difference was observed among the heights, widths, and thicknesses of the left and right sides of the cortical bone of the mandibular body cross sections. From the midline to the farthest point, the height and lower one-third thickness of the lingual cortical bone of the mandibular body cross sections gradually decreased, whereas the width of the upper cross section and upper one-third thickness of the buccal cortical bone gradually increased. Significant difference was observed in some measured values. Conclusion After MC enter into the mandibular foramen, it moved away from the lingual to the buccal bone but gradually returned to the lingual bone; its general course is closer to the lingual bone. The mandibles of males are thicker than those of females. CBCT can accurately display the course of MC and its relationship with the surrounding structures.

Objective This study aimed at using cone beam computed tomography (CBCT) to study the influence of prolonged unilateral posterior teeth loss on bilateral condylar morphology. Methods  The CBCT images of 30 patients with prolonged unilateral posterior teeth loss and 30 healthy people as controls were corrected. Mimics 15.0 software was used to measure volume, area, distance, and bone density of condyle. The results were statistically analyzed. Results The volume and bone density of condylar head and the entire condyle on missing teeth side were less than the contralateral side (P<0.05). The area and bone density of condylar transverse plane were greater than the contralateral side (P<0.05). Conclusion  After prolonged unilateral posterior teeth loss, adaptive reconstruction occurs in the bilateral condyles, and condyle of missing teeth side is smaller than the contralateral side.

Objective  A study was conducted to investigate the relevant applied technique and clinical value of endoscope-assisted repair of zygomatic arch fracture. Methods  A total of 10 cases of unilateral zygomatic arch fracture and 8 cases of unilateral zygomatic fracture were included. Reduction and fixation of the zygomatic arch in all cases were performed via a small face incision by an endoscope. Endoscope-assisted repair allowed exposure of zygomatic arch fracture and ended the anatomy of the reset. Zygomatic arch was stabilized with titanium plates. Results  Symmetric malar was achieved in all cases after operation. Patients did not show difficulty in opening the mouth. No chewing problems or severe complications were evident. This method had the advantage of hidden incision, and it did not leave scars on the face. Postoperative CT examination showed excellent reduction of zygomatic arch fracture and good fixed position of titanium plate. Conclusion  Endoscope-assisted repair of zygomatic arch fracture via a small face incision can be an alternative operation for zygomatic arch fracture. Patients are less traumatized. There are fewer complications. A good reduction of fracture is achieved.

Objective  A study was conducted to evaluate the clinical application of sialendoscopy combined with conventional laparoscopy in a 30 degree angle in depth salivary calculus of submandibular glands. Methods  A total of seventeen patients were presented with repeated swelling in the unilateral submandibular area from June 2013 to August 2015. All patients underwent CT examinations of the mandible and salivary gland function imaging preoperatively. Sialoendoscopy and conventional endoscopy were applied to do intraoral lithotomy. Among the study group, thirteen cases were males and four cases were females. A total of twelve were left cases and five were right cases. Results Seventeen patients had deep positive calculus in the submandibular glands under CT. Photo technetium function was basically normal, whereas secretion of ipsilateral decreased significantly in salivary function tests. Double endoscope assisted surgeries were performed successfully through the mouth to remove the stones. The operation time was (42+21) min. There were no obvious complications in perioperative periods. Conclusion Intraoral lithotomy assisted by sialoendoscopy and conventional laparoscopy for deep stones in the submandibular glands is a new technique. This technique will possibly lead to complete avoidance of gland resection because of early deep sialolithiasis.

Objective To review and analyze the risk factors of postoperative surgical site infection (SSI) in geriatric patients who undergo surgical treatment of oral squamous cell carcinoma. Methods A retrospective study was conducted on 143 geriatric patients who have undergone surgical treatment of oral squamous cell carcinoma. Factors were classified into four types, namely, characteristics, tumor factors, general comorbidity factors, and perioperative factors. The primary outcome variable was the presence of SSI. A logistic stepwise regression model was used for the subsequent multivariate analysis, wherein only significant risk factors in the univariate analysis were included. Results Among 143 cases, 33 showed postoperative SSI. Results of univariate analysis indicated that risk factors included age, body mass index (BMI), tumor location, tumor size, diabetes, chronic obstructive pulmonary disease, American Society of Anesthesiologists (ASA) score, Charlson comorbidity index (CCI), adult comorbidity evaluation-27 (ACE-27) score, previous radiotherapy, reconstructive method, operation time, and blood transfusion. Among these factors, six parameters were identified to have a significant factor association with the development of SSI, namely BMI, diabetes, ASA score, ACE-27 score, operation time, and reconstructive method. Conclusion Special attention should be given to factors associated with the development of SSI before operation of geriatric patients with oral squamous cell carcinoma.

Objective  To explore the effects of aspirin and inflammation on the maturation and function of dendritic cells (DC) on the supernatant of VX-2 squamous cell carcinoma. Methods  The rabbit buccal VX-2 squamous cell carcinoma models with inflammation were established by tumor particle implantation, mechanical trauma, and high sugar diet. The rabbits were divided into three groups. For the experimental group (rabbit buccal VX-2 squamous cell carcinoma with local inflammation), aspirin were given by gavage for three consecutive days. For the control group (rabbit buccal VX-2 squamous cell carcinoma with local inflammation), normal saline was given by gavage for three consecutive days. For the blank group (tumor without inflammation), normal saline was given by gavage for three consecutive days. Each tumor specimens were collected in three days and made into tissue homogenate. The supernatant was collected after centrifugation. Normal rabbit peripheral blood mononuclear cells were separated and co-cultured with different states of supernatant. The expression of DC surface markers CD83, CD86, and human leukocyte antigen-DR (HLA-DR) were detected by flow cytometry. The state of function of DC was tested by mixed lymphocyte reaction. Results  The positive rate of CD83, CD86, and HLA-DR of the experimental and control groups were both lower than that of the blank group (P<0.05). In addition, the ability to stimulate T cell proliferation of the experimental and control groups were weaker than that of the blank group (P<0.05). No significant difference was observed between the experimental and control groups (P>0.05). Conclusion  Inflammation may inhibit the function and expression of CD83, CD86, and HLADR of DC. The short-term administration of aspirin is not conducive to the phenoty and function of DC in a rabbit buccal VX-2 squamous cell carcinoma inflammatory environment.

Objective To study the effects of RhoA down-regulation by RNA interference on the invasion of tongue carcinoma Tca8113 and SCC-4. Methods Determination of the human RhoA sequence as well as the design and construction of a short specific small interfering RNAs (siRNA) were performed. The siRNA of RhoA gene was transfected into human tongue squamous cell carcinoma Tca8113 and SCC-4 cells line by Lipofectamine 2000. Quantitative real-time polymerase chain reaction was used to examine the mRNA expression levels of RhoA. Protein expressions of mRNA, galectin-3, and matrix metalloproteinase (MMP)-9 were evaluated by Western blot. Transwell invasion assay was performed to assess the invasion ability of tongue carcinoma. Results RhoA expressions in Tca8113 and SCC-4 cells were reduced significantly after transfection of RhoA-siRNA. Protein levels of galectin-3 and MMP-9 were also down-regulated significantly. Invasion ability was inhibited as well. Conclusion RhoA-siRNA can effectively inhibit RhoA expression in Tca8113 and SCC-4 cells. The invasion ability of tongue carcinoma cells decreased with down-regulation of the protein expressions of galectin-3 and MMP-9, indicating that RhoA-siRNA can inhibit invasion of tongue carcinoma. Results show that RhoA may play an important role in the processes of invasion and metastasis of tongue carcinoma.

Objective  This study aimed to investigate the expression of midkine (MK) and microvessel density (MVD) in patients with salivary adenoid cystic carcinoma (SACC) and its clinical significance, as well as detect the correlation between the expression of MK and MVD in SACC. Methods  Immunohistochemistry analysis (SP method) for MK and MVD were performed on 60 cases of SACC and 26 cases of normal salivary gland tissue. The expression of MK and MVD, as well as the correlation between the expression of MK and MVD in SACC were detected. Results  In SACC, the MK expression rate was 70.0% (42/60), and MK was not expressed in normal tissue. Statistical significance was found between SACC and normal tissue (P<0.05). The MVD values in SACC and normal salivary gland tissues were 38.73±8.96 and 11.15±3.33, respectively. These values were statistically significant (P<0.05). The expression levels of MK and MVD were unrelated to age, gender, and type in SACC (P>0.05), but correlated with tumor size, lymph node metastasis, and tumor–node–metastasis in SACC (P<0.05). The expression of MK and MVD was positively correlated with SACC (r=0.560, P<0.05). Conclusion  SACC is correlated with the expression of MK protein and the increase in MVD, which may be some of the early diagnostic markers in SACC.

Objective  A study was conducted to investigate the effects of Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) on the expression of regulated upon activation normal T-cell expressed and secreted (RANTES) and fractalkine in human umbilical vein endothelial cells (HUVECs). Methods  HUVECs were incubated with different concentrations of Pg-LPS (200, 500, and 1 000 ng·mL⁻¹) for 1, 6, 12, and 24 h, respectively. Then real time quantitative polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent method (ELISA) were adopted to detect the protein levels and mRNA levels of RANTES and fractalkine. Results  The RANTES protein levels and mRNA levels, as well as fractalkine mRNA levels, were significantly higher in all experimental groups of 1, 6, and 12 h than in the control group (P<0.05), except the expression of RANTES mRNA in 200 ng·mL⁻¹ group of 12 h and RANTES protein in 200 ng·mL⁻¹ group of 1 h. The expression levels of RANTES mRNA and fractalkine mRNA were highest in 1 000 ng·mL⁻¹ group of 6 h and were 4.88- and 6.20-fold higher, respectively, than those in the control group. The expression levels of RANTES protein, mRNA, and fractalkine mRNA decreased 6 h after stimulation, and were significantly higher than those in the control group (P<0.05) in the 500 ng·mL⁻¹ group of 24 h. There was a significant difference between the expression of fractalkine mRNA in 1 000 ng·mL⁻¹ group of 6 and 12 h than in the control group (P<0.05). Conclusion  Pg-LPS infection might up-regulate the expression of RANTES and fractalkine in HUVEC, and such expression is important in the development of atherosclerosis.

Objective  To observe the dynamic changes of membrane-bound proton-translocating ATPase (F-ATPase) in the development of dental caries, the expression of Streptococcus mutans F-ATPase under different pH concentrations and during the development of dental caries is analyzed. Methods  Streptococcus mutans cultured under different pH (pH4.0-7.0) concentrations and containing 5% glucose and no glucose containing BHI were collected. RNA was extracted. Subsequently, F-ATPase gene was detected using real-time polymerase chain reaction. Male Wistar rats were divided randomly into caries group and control group. The rats in the caries group were fed caries feed and 5% glucose water, whereas those of control group were fed normal feed. Total RNA was extracted from plaque samples, which were collected from rats’ oral cavity every two weeks. F-ATPase gene was detected by real-time PCR. In the 11th week, the upper and lower jaw bone specimens of rats were taken, and molar caries damage assessed. Results  The expression of F-ATPase in the caries group was higher than that in the control group (P<0.05). In addition, the gene was expressed highest in pH5.0 and the lowest in pH4.0 (P<0.05). 2) The expression of F-ATPase progressively increased during the caries development in both groups; expression in the caries group was higher than that in control group (P<0.05). Conclusion  Acid-resisting viru-lence factor F-ATPase is related closely with the incidence and development of dental caries.

Maxillary transverse growth is inhibited by congenital cleft, early surgical scar strain, and oppression of lip muscles in patients with cleft lip and palate. Clinical manifestations have shown severely constricted maxilla, insufficient maxillary width, mismatch of upper and lower dental arches, and crossbite. Alveolar bone graft and arch expansion can effectively correct the deficiency in maxillary width. This paper discusses the timing and success rate of alveolar bone graft, as well as the relationship between alveolar bone graft and arch expansion. Secondary alveolar bone graft is optimally performed before permanent canine eruption, especially when the teeth have formed between half and three quarters of their roots. Rapid maxillary expansion prior to alveolar bone graft is beneficial because this process increases the gap of the cleft, expands bone graft, and reduces the difficulty. However, the stability of this process remains controversial. Small-scale studies have reported that rapid maxillary expansion after alveolar bone graft can open the midpalatal suture without bone graft loss. Slow maxillary expansion can provide continuous light forces to reconstruct the bone. However, these studies are coordinated with fixed orthodontic treatment. Further research is necessary to determine the effects of maxillary expansion on long-term stability of teeth.

Polymorphonuclear neutrophil leukocyte(PMN) is an important member of the human immune cells. Recent years, the recognition of the PMN function and the relationship between PMN and periodontitis have been updated. Besides the pathogens killing and phagocytosis, PMN also play an important role in immunoregulation and proresolving. The main-taining of PMN homeostasis is an intricate process and the precondition of defense function, which involves activation, adhe- sion, recruitment, apoptosis and efferocytosis. The regulatory mechanism of PMN homeostasis called neutrophil rheostat, it works through several cytokines and cells. Any factors that break the homeostasis will result in the damage of host immunity, and may relate to the occurrence of periodontitis. Moreover, PMN dysfunction, because of host factors or microorganism factors, is closely related to periodontitis, especially those associated with systemic diseases and gene defect.

Cervical necrotizing fasciitis (CNF) is an aggressive infection associated with high mortality. Various complications have been described in previous literature. However, internal jugular vein thrombosis is rare in such lesions. We presented a case of internal jugular vein thrombosis caused by CNF and analyzed related literature.